Vicilin variants and the resistance of cowpea (Vigna unguiculata) seeds to the cowpea weevil (Callosobruchus maculatus)

Effect of trypsin inhibitor from Crotalaria pallida seeds on Callosobruchus maculatus (cowpea weevil) and Ceratitis capitata (fruit fly)

“…To examine the effects of CpaTI on C. maculatus development, the artificial seed system previously developed by Macedo et al [29] was used. Artificial seeds (ca.…”

Variant vicilins from a resistant Vigna unguiculata lineage (IT81D-1053) accumulate inside Callosobruchus maculatus larval midgut epithelium

“…The observed antibiosis was firstly attributed to relatively high levels of trypsin inhibitors (Gatehouse et al, 1979), but subsequently it was demonstrated that the resistance was in fact caused by the presence of variant vicilins (Macedo et al, 1993). The defensive role of variant vicilins against the cowpea beetle was first reported from the genotype IT81D-1045, that is derived from the cultivar TVu 2027 and is also resistant to C. maculatus (Macedo et al, 1993).…”

“…The observed antibiosis was firstly attributed to relatively high levels of trypsin inhibitors (Gatehouse et al, 1979), but subsequently it was demonstrated that the resistance was in fact caused by the presence of variant vicilins (Macedo et al, 1993). The defensive role of variant vicilins against the cowpea beetle was first reported from the genotype IT81D-1045, that is derived from the cultivar TVu 2027 and is also resistant to C. maculatus (Macedo et al, 1993). The mechanism of action of the variant vicilins appears to be correlated to their resistance to proteolysis by digestive peptidases and their binding affinity to C. maculatus midgut epithelial cell surfaces (Firmino et al, 1996;Sales et al, 2001).…”

“…Vicilins were purified from C. maculatus susceptible (Epace 10) and resistant (IT81D-1053) seeds employing the procedure developed by Macedo et al (1993). Ground seed flour was extracted with 50 mM borate buffer (pH 8.0) for 30 min at room temperature, centrifuged (30 min at 8000 g, 5°C) and the soluble proteins were fractionated by ammonium sulphate precipitation.…”

Vicilins (7S storage globulins) of cowpea (Vigna unguiculata) seeds bind to chitinous structures of the midgut of Callosobruchus maculatus (Coleoptera: Bruchidae) larvae

“…However, other workers (7-10) did not find a significant correlation between the levels of trypsin or cysteine proteinase inhibitors or even a-amylase inhibitors in cowpea seeds and their susceptibility or resistance to infestation with C. maculatus. More recent studies suggest that the resistance of IT81D-1045 seeds to C. maculatus is due to variant forms of vicilins (7S storage proteins) which are resistant to digestion by midgut proteinases and possibly limit food supply to the larvae (11)(12)(13). The mechanism of resistance due to variant vicilins seems to be also linked to their chitin-binding power, a recently discovered property (14)(15)(16)(17).…”